SuzukiSavage.com - Oil Pressure

DragBikeMike

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Oil Pressure
06/06/19 at 13:31:23

I’ve seen a lot of posts and comments related to oil pressure. Seems our engines are prone to worn out camshafts and rocker arms. I wanted to learn more about our top end oiling system so when I did my head exchange I decided to see if I could install a pressure gage to measure oil pressure to the top end.

Our engines use ball and roller bearings in the lower end so there must be some sort of orifice in the system to prevent all the oil from dribbling through the bottom end. I assume that orifice is probably in the right-hand side of the crankshaft where the oil enters from the filter. The built-in restriction might also be in the clutch cover assembly. Anyone have any idea where the built-in restriction is located?

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DragBikeMike

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Re: Oil Pressure
Reply #1 - 06/06/19 at 13:34:20

I initially installed a 0-60 psi gage. I had no idea what sort of pressure to expect and I didn’t want to blow the gage up. As it turns out, 0-60 was way too ambitious. I ended up with a 0-15 psi gage installed. That has a major problem in that when cold, the pressure exceeds the range of the gage, but when hot, the pressure is extremely low. It would be nice if our top ends were fed a steady diet of oil pressurized to about 10 psi, but unfortunately that’s not the case. We’re lookin at pressure that ranges from zero to 3 psi (dependent on engine speed) when the oil is at normal operating temperature. I run 20W-50 oil so you folks running 10W-40 can probably expect less pressure to your top end (I’m gonna guess zero to 2 psi).

Once my engine is up to normal operating temperature, I have zero top end oil pressure from idle to about 2900 rpm. From 3000 rpm to about 3500 rpm I have about 2 to 2.5 psi. Once past 3500 rpm it runs right at 3 psi. The zero psi doesn’t alarm me. I routinely observed zero psi on my Harley. That’s just how these engines with ball & roller bottom ends work. The difference here is the Harley top end didn’t have a cam to lubricate. Our top end does have a cam and there’s a lot of sliding friction to deal with.

When cold, the oil pressure over-ranges the gage. Looks like it runs approximately 20 psi. I must take things easy for about the first minute of operation to prevent the instrument from rotating 360° and hitting the hard stop. Certainly not ideal. I could install a 0-30 psi gage but then it would mostly read zero. We’ll see how things go. If it blows up, I will let you know.

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DragBikeMike Serious Thumper Offline SuzukiSavage.com Rocks! Posts: 4166 Honolulu	Re: Oil Pressure Reply #2 - 06/06/19 at 13:35:20 I installed the gage line in the cylinder head cover at the 130 mm bolt hole in the rear right-hand corner. This hole serves as the passage for the top end oil. It was easy to do and so far, has worked fine with no leaks.
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DragBikeMike

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Re: Oil Pressure
Reply #3 - 06/06/19 at 13:36:26

Here’s a look at the installed fitting. I sealed it with epoxy to give me that little bit of extra assurance that things will stay oil-tight. The epoxy also provides a little bit of extra support for the fitting. It only has about 1/8” thread engagement but that’s certainly adequate when you consider how much pressure it is subjected to.

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Press_Gage_Ftg_1_2.JPG

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DragBikeMike Serious Thumper Offline SuzukiSavage.com Rocks! Posts: 4166 Honolulu	Re: Oil Pressure Reply #4 - 06/06/19 at 13:37:11 This is what the fitting looks like on the engine.
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DragBikeMike

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Re: Oil Pressure
Reply #5 - 06/06/19 at 13:38:39

I used NOS compression fittings and NOS 1/8” nylon tubing to connect the head cover to the gage. The tubing is rated for 500 psi but only 200°F. That makes me a bit uncomfortable. But as I mentioned, it’s working fine so far, and I’ve got that motor good and hot several times since I installed the gage line. No leaks yet. I left the beauty covers off so that I could keep an eye on the fitting until I have good confidence that it is a sound installation. I will have to mill a notch in the cover for the gage line and fitting. It shouldn’t look too bad.

Here’s how the gage looks from the rider’s view. I like it. It’s a liquid filled gage intended for high vibration applications.

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DragBikeMike

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Re: Oil Pressure
Reply #6 - 06/06/19 at 13:39:18

Based on the pressure readings that I am seeing, the comments regarding not letting the engine idle for long periods of time are probably darned good advice. I also wouldn’t cruise around at engine speeds below 3000 rpm. Get that little thumper revved up. The readings also make me think about those holes in the cam lobes. I imagine the holes could make it even harder to build up oil pressure. What an interesting problem.

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verslagen1 YaBB Moderator ModSquad Offline Where there's a will, I want to be in it. Posts: 28755 L.A. California Gender:	Re: Oil Pressure Reply #7 - 06/06/19 at 14:54:54 DragBikeMike wrote on 06/06/19 at 13:31:23: The built-in restriction might also be in the clutch cover assembly. Anyone have any idea where the built-in restriction is located? Yes, it's at the back end of the oil channel that runs along the top of the case and clutch cover.
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Ruttly

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Re: Oil Pressure
Reply #8 - 06/06/19 at 14:56:33

Smaller hole DBM ? Synflex tubing works well till exposed to heat , pressure on the inside and too much heat it blisters and pops similar to how aluminum melts ,absorbs heat then melts into a blob without warning. Advise you insulate with maybe some of that silver tubing with that meshed cloth on the inside or at least split wiring loom. Better off with a electric oil pressure sensor & gauge. Sure looks cool ! Are you going to use a fuel ratio gauge ?

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batman

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Re: Oil Pressure
Reply #9 - 06/07/19 at 04:28:31

Vercy's correct ,-Jet ,Oil Gallery 09493-36004 ,can't leave home without it, or installing it backward , or not at all, isn't good either.
Mike , you might try running Rotella T-6 that may drop the press a bit at cold startup ,( Synthetic oil isn't as thick when cold and warms faster) and Vercy found 10w 50 oil to actually make the motor run hotter as compared to 10 w40 ,probably because of lower pressure and increased flow . While there is very low pressure at idle there is splash lubrication provided by the "bathtub" under the cam lobes. Many think that 50 w will protect their engines better in hotter climates and the opposite is true. 40 w oil flows better providing a thicker lay of oil between parts and the increased flow carries heat away at a faster rate.-(it's other job to act as a coolant)

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« Last Edit: 06/07/19 at 13:12:22 by batman »

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DragBikeMike

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Re: Oil Pressure
Reply #10 - 06/07/19 at 23:37:18

I see this "oil control orifice" Verslagen. I'm baffled. With an open bearing bottom end you need to restrict flow to all those ball & roller bearings otherwise all the pump output will simply dribble away through the lower end and no oil will flow to the top end. Need some pressure to force the oil up there. Do you happen to know if that oil control orifice is restricting flow to the bottom end? It's location would imply that it's restricting flow to the top end, but this little thumper's design has surprised me more than a time or two. Is there any sort of oil flow diagram available?

I noted that there is a seal in the clutch cover that appears to engage the end of the crankshaft. I assumed that was the point where oil was forced into the crank to lubricate the rod bearing and probably also provides oil to the main bearings. On Harley's, folks install orifices in the crankshaft to control the flow of oil to the rod & mains. Installing a smaller orifice in the crankshaft increases pressure to the top end. Does anyone know if there is any sort of orifice in the right side of the crankshaft? Anyone got a crank laying around that they could take a peek in?

Yes Rutly, I am working on an A/F ratio meter installation, but it will be a temporary setup just for test & tune. I will leave the O2 sensor installed but will remove the meter assembly after testing. It's a cheap narrow-band K&N unit and it's butt-ugly. If it works decent it will be invaluable when I install the S&S carb. I'm sure that will be a real challenge to tune and the A/F meter will most certainly make things easier.

I have no plans to switch oil. I am very comfy with the Mobil 1 Synthetic V-Twin 20W-50. It's formulated for air-cooled engines, good for gearboxes and clutches. The LS650 owners manual lists 20W-50 as a suitable lubricant for the climate here in the islands, and virtually all manufacturers and refiners recommend heavier weight oil for elevated temperatures. I'm sure the Rotella is totally fine but I've got this fetish for the Mobil 1 product. Been runnin it for years. It's a love affair.

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Dave

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Re: Oil Pressure
Reply #11 - 06/08/19 at 03:36:17

The oil flow path was shown in this thread......looks like the pictures no longer open.

I have a crank and engine that are on my bench......I will look around and see what I can figure out about what that small brass fitting does, and where it is limiting flow.

DBM - Did you drill the center of your DR650 cam to open up the center hole to LS650 size? If not......our engines upper end oil pressure might even be less with an LS650 cam that has a larger center hole and holes in the cam lobes.

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verslagen1 YaBB Moderator ModSquad Offline Where there's a will, I want to be in it. Posts: 28755 L.A. California Gender:	Re: Oil Pressure Reply #12 - 06/08/19 at 08:09:06 http://suzukisavage.com/cgi-bin/YaBB.pl?num=1151246239/0#1
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batman

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Re: Oil Pressure
Reply #13 - 06/08/19 at 08:28:26

If I'm not mistaken ,the orifice restricts flow to the transmission area.
Mike, 20w50 isn't rated for any higher temperature than 10w40 ,
Verslagen's test was done at his local, southern CA . I doubt your temperatures are any higher than his. You reference HD's but as you said they don't have overhead cams , and being long stroke motors have higher piston to wall speed for the same rpm as a Savage, the rear piston also suffers from a lack of cooling air ,all good reasons to use 20w50 , but they are not present in the Savage and the reason a 40w oil functions better in them. Your love affair may just be a habit ,you may be happy ,but is your bike?

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verslagen1 YaBB Moderator ModSquad Offline Where there's a will, I want to be in it. Posts: 28755 L.A. California Gender:	Re: Oil Pressure Reply #14 - 06/08/19 at 09:04:09 batman wrote on 06/08/19 at 08:28:26: Verslagen's test was done at his local, southern CA . I doubt your temperatures are any higher than his. http://suzukisavage.com/cgi-bin/YaBB.pl?num=1283117891/0
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